Mmm, this could be. But, it shouldn’t be. Um, can use attach a wire between the BOOT0 and RST pin and then plug it back into your computer.
The DFU bootloader should appear as a device. If this is the case then you can recover it using the DFU util built-in to the IDE. You’ll just need to install a few command lines tools for this to work. Let me know if the device appears as a DFU bootloader in linux and I’ll tell you how to proceed. If you can’t find the device you can also just try blindly. You’ll need to install these things:
sudo apt-get install libusb-1.0 python-pip
sudo pip install pyusb